ABSTRACT

The Marine water is under risk of high pollution due to the amount of heavy metals that gets into it by various means which becomes toxic when they exceed the permissible limit. Although there are numerous health benefits of Tilapia fish and Flying fish (Exocoetus volitans), Prawn - giant tiger prawn, Crab and Periwinkle consumption, this can be compromised by the presence of toxic metals such as Fe, Zn, Cu, and Cr which can have harmful effects on the human body at toxic levels. This study was carried out in Ibaka estuarine, Mbo LGA, Akwa Ibom state and it was done to determine the heavy metal content in the river as well as the accumulation of heavy metals in the tissues of the aquatic fauna. The river was divided into 3 sampling stations and there was collection of water and aquatic fauna samples at each station. Digestion of each samples was done before using atomic absorption spectrometry to determine each heavy metal and acetylene-air flame was used. In the present study, Thc and Hg were not detected in the water samples and NO; exceeded the permissible limits set for water quality both for the ecosystem and human health. There was bioaccumulation of heavy metals in the tissues of the fish, prawn, crab and periwinkle. Periwinkle had the highest concentration of all the metals in its tissues. Fe and Zn exceeded the permissible limit set by WHO/FAQ. Mn and Cu were within the acceptable limits while Cr, Cd, Ni, Pb, and V were not detected in the tissues of these aquatic fauna. Nevertheless, the study showed that there was no excess trace metal exposure of the water and fauna but due to industrialization, rapid urbanization and exposure to aquatic pollutants, there is need for continuous monitoring of the ecosystem. This study adds information to Ibaka Estuarine, Mbo Local Government Area, Akwa Ibom state which hitherto had little or no information.